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SPECIFICATION..

T0 ALL WHOM I'llVIAY CONCERN:

Be it known that I, T. Gr. ARNOLD, of thercity, county, and State of NewYork, have invented certain new` and useful improvements in Chucks forholding metal tubing, or other articles or substances, in lathes; and Ido hereby declare that the following is a full description ofV the same.

The nature of my invention consists in 'iirst' forming the head of thechuck and stock or centre (upon which it is secured on the mandrel ofthe lathe) solid, and of one piece of metal; second, in securing thejaws of the chuck into the head-piece by centre pins, so that the outerends of the jaws may have an expanding motion, but at the same timehld'steadily and firmly at their back ends in the head-piece by thecentre pins, and thusenable the jaws to bite with more sharpness andsolidity than possible-to attain` by any other means of holding the jawsin the head-piece. But to describe my invention more particularly,Iiwill refer to the accompanying drawilxgs,` forming a part of thisspecification, the same letters of reference, wherever they occur,referring to,1ike parts. t

Figure Irisa side view of the chuck. Figure 2 is agout sectionalview ofthe same through the line :e x, fig. 3. Figure 3 is a transverse cutsection ofthe chuck through the line :1:2 fr", fig. 1. Figure 4 is aface view of the chuck. l

LetterjA isthe stockor stem of the chuck) having a solid head-piece, B.In this head-piece are cut'fourl longitudinal slots, C, of about half aninch deep. In these slots are fitted thetang D, of the jaws E, whicharei severally held in the several slots by pins, F, passingtransversely through the tangs and section of the head-v ,piece. Theobject of this mode of securing/the jaws in the head-piece of the chuckis to permit the jaws to have an expanding motion at their outer ends byworking on the pins, F, as a centre of motion, but from their accuracyof tit in the slot prevented from having any lateral or yielding motionwhen clamping the pipe or other article.Y between the. jaws during theoperation of screwing up lthe binding-'nut G- on the outer ends of thejaws. It

will be obvious thatfor the purpose of causing the jaws to bitediferent'sizes of tubes, or other articles, within the limited capacityof the chuck, the outer ends of the external surface of the jawsare madetapering, so that as the nut draws up the taper their ends arecontracted upon the article, and it is thereby held firmly andsolidly'as if in a vise; and as the jaws are made in four sections they willreadily adapt themselves to anylittle inequal-- ities in the surface ordiameter of the tubing in the act of screwing the nut on them. It willalso beobserved that freni thel imitedfcapaeity of the chuck it is notdesigned for a universal chuck.' The special objeet`fof the invention isforfthe use of gas-pipe ittersand othersl engaged in boring and turningsmall articles of uniform: patterm'or nearly so, but want great strengthand vaccuracy as well l.as durability, and especially facility of rapidadjustment on account of the immensenumber of such small articlesrequired to be turned out daily to make it profitable at the'pricesusually charged for such articles. My invention is,.the refore, toaccomplish all these advantages. Y Letter. represents au ordinarygas-burner, as adjusted in the chuclgpthe end of which fits 4into'asocket, J, in the centre of the head-piece. This socket, howcvei-,is nota materialV fixture, as a central openingv in the head-piece will answerequally well. And in'making the chuck for some purposes it is designed.

to make the head-piece with a. central opening in the like manner as theordinary chuck, so as' to be screwed on the end ofthe mandrel instead ofusing the stem A, as represented. V

Having nowhdescribed my invention, I will proceed to set forth what Iclaim and desire to secure by Letters Patentof 'the United States: A

I claim the arrangement of the expanding'jaws E,'pivoted to the solidhead-piece B, constructed and operating substantially as hereinbeforeset forth and for the purposes described. l

T. G. ARNOLD.

VWitnesses:

L. BARRET,

Brenn L. H. FrNeH.

